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arXiv · 1611.06378

Frustration induced one-dimensionality in the isosceles triangular antiferromagnetic lattice of $\delta$-(EDT-TTF-CONMe$_{2}$)$_{2}$AsF$_6$

B. Náfrádi·A. Antal·T. Fehér·L. F. Kiss·C. Mézière·P. Batail·L. Forró·A. Jánossy
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Abstract

The $1/4$-filled organic compound, $\delta$-(EDT-TTF-CONMe$_{2}$)$_{2}$AsF$_6$ is a frustrated two-dimensional triangular magnetic system as shown by high-frequency (111.2 and 222.4 GHz) electron spin resonance (ESR) and structural data in the literature. The material gradually orders antiferromagnetically below 40~K but some magnetically disordered domains persist down to 4 K. We propose that in defect free regions frustration prevents true magnetic order down to at least 4 K in spite of the large first- and second-neighbor exchange interactions along chains and between chains, respectively. The antiferromagnetic (AFM) order gradually developing below 40 K nucleates around structural defects that locally cancel frustration. Two antiferromagnetic resonance modes mapped in the principal planes at 4~K are assigned to the very weakly interacting one-dimensional molecular chains in antiferromagnetic regions.

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B. Náfrádi, A. Antal, T. Fehér, L. F. Kiss, C. Mézière, P. Batail, L. Forró, A. Jánossy. 2016-11-19. Frustration induced one-dimensionality in the isosceles triangular antiferromagnetic lattice of $\delta$-(EDT-TTF-CONMe$_{2}$)$_{2}$AsF$_6$. https://doi.org/10.1103/physrevb.94.174413

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